Impedance measurement system

ABSTRACT

A system for performing at least one impedance measurement on a biological subject, the system including a measuring device having a first housing including spaced pairs of foot drive and sense electrodes provided in electrical contact with feet of the subject in use, a second housing including spaced pairs of hand drive and sense electrodes provided in electrical contact with hands of the subject in use, at least one signal generator electrically connected to at least one of the drive electrodes to apply a drive signal to the subject, at least one sensor electrically connected to at least one of the sense electrodes to measure a response signal in the subject and a measuring device processor that at least in part controls the at least one signal generator, receives an indication of a measured response signal from the at least one sensor and generates measurement data indicative of at least one measured impedance value and a client device in communication with the measuring device, the client device being adapted to receive measurement data allowing the client device to display an indicator associated a result of the impedance measurement.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/957,563, filed Apr. 19, 2018, and published on Aug. 23, 2018 as U.S.Patent Application Publication No. 2018/0235508, which is a continuationof International Patent Application No. PCT/AU2016/051070, filed Nov. 8,2016, and published in English on May 18, 2017 as WO/2017/079794, whichclaims the benefit of Australian Patent Application No. 2015904624,filed Nov. 10, 2015, U.S. Provisional Application No. 62/346,941, filedJun. 7, 2016, and U.S. Provisional Application No. 62/380,267, filedAug. 26, 2016, each of which are incorporated by reference in theirentirety.

BACKGROUND

Embodiments described herein relate to a system and method forperforming at least one impedance measurement on a biological subject.

The reference in this specification to any prior publication (orinformation derived from it), or to any matter which is known, is not,and should not be taken as an acknowledgment or admission or any form ofsuggestion that the prior publication (or information derived from it)or known matter forms part of the common general knowledge in the fieldof endeavour to which this specification relates.

WO2007/002991 describes apparatus for performing impedance measurementson a subject. The apparatus includes a first processing system fordetermining an impedance measurement procedure and determininginstructions corresponding to the measurement procedure. A secondprocessing system is provided for receiving the instructions, using theinstructions to generate control signals, with the control signals beingused to apply one or more signals to the subject. The second processingsystem then receives first data indicative of the one or more signalsapplied to the subject, second data indicative of one or more signalsmeasured across the subject and performs at least preliminary processingof the first and second data to thereby allow impedance values to bedetermined.

SUMMARY

In one broad form embodiments described herein seek to provide a systemfor performing at least one impedance measurement on a biologicalsubject, the system including:

-   -   a) a measuring device having:        -   i) a first housing including spaced pairs of foot drive and            sense electrodes provided in electrical contact with feet of            the subject in use;        -   ii) a second housing including spaced pairs of hand drive            and sense electrodes provided in electrical contact with            hands of the subject in use;        -   iii) at least one signal generator electrically connected to            at least one of the drive electrodes to apply a drive signal            to the subject;        -   iv) at least one sensor electrically connected to at least            one of the sense electrodes to measure a response signal in            the subject; and,        -   v) a measuring device processor that at least in part:            -   (1) controls the at least one signal generator;            -   (2) receives an indication of a measured response signal                from the at least one sensor; and,            -   (3) generates measurement data indicative of at least                one measured impedance value; and,    -   b) a client device in communication with the measuring device,        the client device being adapted to receive measurement data        allowing the client device to display an indicator associated a        result of the impedance measurement.

Typically the drive and sense electrodes are spaced apart metal plates.

Typically the foot drive and sense electrodes are spaced apart by atleast one of:

-   -   a) at least 8 cm;    -   b) at least 8.2 cm;    -   c) at least 8.4 cm;    -   d) up to 9 cm;    -   e) up to 8.8 cm;    -   f) up to 8.6 cm;    -   g) between 8 cm and 9 cm;    -   h) between 8.2 cm and 8.8 cm;    -   i) between 8.4 cm and 8.6 cm; and,    -   j) approximately 8.5 cm.

Typically the foot drive electrode has a surface area that is at leastone of:

-   -   a) at least 110 cm;    -   b) at least 115 cm;    -   c) at least 120 cm;    -   d) at least 122 cm;    -   e) up to 140 cm;    -   f) up to 135 cm;    -   g) up to 130 cm;    -   h) up to 218 cm;    -   i) between 110 cm² and 140 cm²;    -   j) between 115 cm² and 135 cm²;    -   k) between 120 cm² and 130 cm²;    -   l) between 122 cm² and 128 cm²;    -   m) approximately 125 cm²; and,    -   n) approximately 124.3 cm².

Typically the foot sense electrode has a surface area that is at leastone of:

-   -   a) at least 35 cm;    -   b) at least 40 cm;    -   c) at least 45 cm;    -   d) at least 50 cm;    -   e) up to 70 cm;    -   f) up to 65 cm;    -   g) up to 60 cm;    -   h) up to 55 cm;    -   i) between 35 cm² and 70 cm²;    -   j) between 40 cm² and 65 cm²;    -   k) between 45 cm² and 60 cm²;    -   l) between 50 cm² and 55 cm²;    -   m) approximately 53 cm²; and,    -   n) approximately 52.6 cm².

Typically the first housing includes a raised lip extending at leastpartially around each pair of foot drive and sense electrodes to therebyguide positioning of a subject's foot relative to the foot drive andsense electrodes in use.

Typically the raised lip is configured to engage at least a heel of thesubject.

Typically the first housing includes feet that support the first housingspaced from a surface.

Typically the feet engage load cells mounted within the first housing,the measuring device processor being adapted to determine a weight of asubject standing on the first housing.

Typically the first housing includes:

-   -   a) a rigid internal plate; and,    -   b) four foot assemblies, each foot assembly including:        -   i) a load cell mounting on an underside of the plate;        -   ii) a foot member; and,        -   iii) a load cell coupled to the load cell mounting and the            foot member so that the load cell deforms upon application            of a load to the rigid plate.

Typically the load cell mounting includes a cylindrical body extendingfrom the plate, the foot member at least partially positioned in andaxially movable within the cylindrical body.

Typically the first housing includes supporting ridges extending alongunderside lateral edges of the first housing.

Typically the hand drive and sense electrodes in each pair are spacedapart by at least one of:

-   -   a) at least 3 cm;    -   b) at least 3.2 cm;    -   c) at least 3.4 cm;    -   d) up to 4 cm;    -   e) up to 3.8 cm;    -   f) up to 3.6 cm;    -   g) between 3 cm and 4 cm;    -   h) between 3.2 cm and 3.8 cm;    -   i) between 3.4 cm and 3.6 cm; and,    -   j) approximately 3.5 cm.

Typically the hand drive electrode has a surface area that is at leastone of:

-   -   a) at least 35 cm;    -   b) at least 38 cm;    -   c) at least 40 cm;    -   d) at least 41 cm;    -   e) up to 50 cm;    -   f) up to 45 cm;    -   g) up to 43 cm;    -   h) up to 42 cm;    -   i) between 35 cm² and 50 cm²;    -   j) between 38 cm² and 45 cm²;    -   k) between 40 cm² and 43 cm²;    -   l) between 41 cm² and 42 cm²;    -   m) approximately 41 cm²; and,    -   n) approximately 41.4 cm².

Typically the hand sense electrode has a surface area that is at leastone of:

-   -   a) at least 35 cm;    -   b) at least 40 cm;    -   c) at least 45 cm;    -   d) at least 46 cm;    -   e) up to 55 cm;    -   f) up to 50 cm;    -   g) up to 49 cm;    -   h) up to 48 cm;    -   i) between 35 cm² and 55 cm²;    -   j) between 40 cm² and 50 cm²;    -   k) between 45 cm² and 49 cm²;    -   l) between 46 cm² and 48 cm²;    -   m) approximately 47 cm²; and,    -   n) approximately 46.8 cm².

Typically the second housing is shaped to at least partially conform toa shape of a subject's hands.

Typically the second housing has a curved upper surface.

Typically a radius of curvature of the hand drive electrode is differentto a radius of curvature of the hand sense electrode.

Typically a radius of curvature of the hand drive electrode is at leastone of:

-   -   a) at least 100 mm;    -   b) at least 110 mm;    -   c) at least 115 mm;    -   d) at least 118 mm;    -   e) up to 150 mm;    -   f) up to 130 mm;    -   g) up to 125 mm;    -   h) up to 122 mm;    -   i) between 100 mm and 150 mm;    -   j) between 110 mm and 130 mm;    -   k) between 115 mm and 125 mm;    -   l) between 118 mm and 122 mm;    -   m) approximately 120 mm; and,    -   n) approximately 119.5 mm;

Typically a radius of curvature of the hand sense electrode is at leastone of:

-   -   a) at least 180 mm;    -   b) at least 200 mm;    -   c) at least 210 mm;    -   d) at least 215 mm;    -   e) up to 260 mm;    -   f) up to 240 mm;    -   g) up to 230 mm;    -   h) up to 225 mm;    -   i) between 180 mm and 260 mm;    -   j) between 200 mm and 240 mm;    -   k) between 210 mm and 230 mm;    -   l) between 215 mm and 225 mm;    -   m) approximately 220 mm; and,    -   n) approximately 218 mm.

Typically the second housing includes a raised portion between each pairof hand drive and sense electrodes, the raised portion defining thumbrecesses to thereby guide positioning of a subject's hands relative toeach pair of hand drive and sense electrodes in use.

Typically raised portion includes two ridges, each ridge extendingtowards a respective hand sense electrodes, and being adapted to bepositioned between a subject's thumb and forefinger.

Typically system includes a support that supports a client device, thesupport being removably mounted to the second housing.

Typically the support includes:

-   -   a) a mounting that removably couples to the second housing; and,    -   b) a frame that receives the client device.

Typically the frame is pivotally coupled to the mounting to allow theframe to be at least one of:

-   -   a) tilted relative to the mounting; and,    -   b) rotated relative to the mounting.

Typically the client device is at least one of a tablet and asmartphone.

Typically the system includes a stand including:

-   -   a) a base that supports the first housing;    -   b) a platform that supports the second housing; and,    -   c) a leg coupled to the base and platform to support the        platform relative to the base.

Typically the leg is curved so that a centre of the platform is offsetfrom a centre of the base.

Typically the leg includes a cavity that receives a lead extendingbetween the first and second housings.

Typically the platform is spaced from the base by a vertical distance ofat least one of:

-   -   a) at least 100 cm;    -   b) at least 103 cm;    -   c) at least 104 cm;    -   d) at least 105 cm;    -   e) up to 110 cm;    -   f) up to 108 cm;    -   g) up to 107 cm;    -   h) up to 106 cm;    -   i) between 100 cm and 110 cm;    -   j) between 103 cm and 108 cm;    -   k) between 104 cm and 107 cm;    -   l) between 105 cm and 106 cm;    -   m) approximately 105.5 cm; and,    -   n) 105.4 cm.

Typically at least one of the first and second housings include keyholemountings, allowing the at least one of the first and second housings tobe removably mounted to the base and platform respectively.

Typically the system includes:

-   -   a) four signal generators, each signal generator being        electrically connected to a respective drive electrode; and,    -   b) four sensors, each sensor being electrically connected to at        least one of the sense electrodes to measure a response signal        in the subject.

Typically the measuring device processor selectively controls the foursignal generators and four sensors to perform a sequence of impedancemeasurements, the impedance measurements including:

-   -   a) segmental impedance measurements; and,    -   b) whole of body impedance measurements.

Typically the system includes four sensors attached to the driveelectrodes to allow the drive electrodes to be used in sensing bodysignals.

Typically the first and second housings contain respective circuitboards interconnected via a lead.

Typically the measuring device includes a communications module forcommunicating with the client device.

Typically the measuring device processor communicates with the clientdevice to at least one of:

-   -   a) determine the at least one measurement to be performed;    -   b) provide a measurement indication to the client device, the        measurement indication being indicative of a measurement being        performed;    -   c) provide measurement data to the client device, the        measurement data being indicative of at least one of:        -   i) measured signals;        -   ii) a body parameter value derived from the measured            signals, the body parameter including at least one of:            -   (1) a respiration parameter;            -   (2) a cardiac parameter;            -   (3) an impedance parameter; and,            -   (4) a weight parameter.

Typically the measuring device processor:

-   -   a) determines a presence of a subject in accordance with signals        from at least one of the load cells and the at least one sensor;    -   b) commences at least one measurement procedure;    -   c) provides a measurement indication to the client device, the        client device being responsive to the measurement indication to        display an indication of at least one of:        -   i) information regarding the measurement process;        -   ii) measured signals;        -   iii) a body parameter value;        -   iv) a body status indicator;        -   v) instructions to the subject; and,        -   vi) a question for the subject.    -   d) performs the measurement; and,    -   e) provides measurement data to the client device, the        measurement data being indicative of at least one of:        -   i) measured signals; and,        -   ii) a body parameter value derived from the measured            signals, the body parameter including at least one of:            -   (1) a respiration parameter;            -   (2) a cardiac parameter;            -   (3) an impedance parameter; and,            -   (4) a weight parameter.

Typically the measuring device processor:

-   -   a) detects when a subject is standing on the foot unit in        accordance with signals from at least one of the load cells;        and,    -   b) causes a weight measurement procedure to be performed using        signals from the load cells.

Typically the measuring device processor:

-   -   a) detects when a subject's hands and feet are positioned in        contact with the hand and feet electrodes in accordance with        signals from the at least one sensor; and,    -   b) causes a measurement procedure to be performed including at        least one of:        -   i) an impedance measurement procedure;        -   ii) a cardiac measurement procedure; and,        -   iii) a respiration measurement procedure.

Typically the measuring device performs a cardiac or respirationmeasurement procedure by:

-   -   a) using at least one sensor to measure at least one body signal        in the subject via at least the sense electrodes; and,    -   b) analysing the body signals to determine at least one of:        -   i) a respiration parameter value; and,        -   ii) a cardiac parameter.

Typically the measuring device processor:

-   -   a) detects when a subject is standing on the foot unit in        accordance with signals from at least one of the load cells;    -   b) provides weight measurement indication to the client device,        the client device being responsive to the weight measurement        indication to instruct the subject to stand for a weight        measurement;    -   c) performs the weight measurement;    -   d) provides a body measurement indication to the client device,        the client device being responsive to the body measurement        indication to instruct the subject to place their feet and hands        on the respective electrodes;    -   e) detects when a subject's hands and feet are positioned in        contact with the hand and feet electrodes in accordance with        signals from the at least one sensor;    -   f) commences a measurement procedure to be performed including        at least one of:        -   i) an impedance measurement procedure;        -   ii) a cardiac measurement procedure; and,        -   iii) a respiration measurement procedure; and,    -   g) provides measurement data to the client device, the client        device being responsive to the measurement data to:        -   i) generate at least one body status indicator using the            measurement data; and,        -   ii) display an indication of the at least one body status            indicator to the subject.

In one broad form embodiments described herein seek to provide a methodfor performing at least one impedance measurement on a biologicalsubject, the system including:

-   -   a) using a measuring device having:        -   i) a first housing including spaced pairs of foot drive and            sense electrodes provided in electrical contact with feet of            the subject in use;        -   ii) a second housing including spaced pairs of hand drive            and sense electrodes provided in electrical contact with            hands of the subject in use;        -   iii) at least one signal generator electrically connected to            at least one of the drive electrodes to apply a drive signal            to the subject;        -   iv) at least one sensor electrically connected to at least            one of the sense electrodes to measure a response signal in            the subject; and,        -   v) a measuring device processor that at least in part:            -   (1) controls the at least one signal generator;            -   (2) receives an indication of a measured response signal                from the at least one sensor; and,            -   (3) generates measurement data indicative of at least                one measured impedance value; and,        -   vi) using a client device in communication with the            measuring device, the client device being adapted to receive            measurement data allowing the client device to display an            indicator associated a result of the impedance measurement.

In one broad form embodiments described herein seek to provide a systemfor performing at least one impedance measurement on a biologicalsubject, wherein the system including a measuring device processor that:

-   -   a) determines a presence of a subject in accordance with signals        from at least one of a load cell and at least one sensor;    -   b) provides a measurement indication to a client device, the        client device being responsive to the measurement indication to        display an indication of at least one of:        -   i) information regarding the measurement process;        -   ii) measured signals;        -   iii) a body parameter value;        -   iv) a body status indicator;        -   v) instructions to the subject; and,        -   vi) a question for the subject.    -   c) causes the measurement to be performed; and,    -   d) provides measurement data to the client device, the        measurement data being indicative of at least one of:        -   i) measured signals; and,        -   ii) a body parameter value derived from the measured            signals, the body parameter including at least one of:            -   (1) a respiration parameter;            -   (2) a cardiac parameter;            -   (3) an impedance parameter; and,            -   (4) a weight parameter.

In one broad form embodiments described herein seek to provide a methodfor performing at least one impedance measurement on a biologicalsubject, wherein the method includes, in a measuring device processor:

-   -   a) determining a presence of a subject in accordance with        signals from at least one of a load cell and at least one        sensor;    -   b) providing a measurement indication to a client device, the        client device being responsive to the measurement indication to        display an indication of at least one of:        -   i) information regarding the measurement process;        -   ii) measured signals;        -   iii) a body parameter value;        -   iv) a body status indicator;        -   v) instructions to the subject; and,        -   vi) a question for the subject.    -   c) causing the measurement to be performed; and,    -   d) providing measurement data to the client device, the        measurement data being indicative of at least one of:        -   i) measured signals;        -   ii) a body parameter value derived from the measured            signals, the body parameter including at least one of:            -   (1) a respiration parameter;            -   (2) a cardiac parameter;            -   (3) an impedance parameter; and,            -   (4) a weight parameter.

It will be appreciated that the broad forms of the embodiments describedherein can be used in conjunction and/or independently, and reference toseparate broad forms in not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

An example of the embodiments described herein will now be describedwith reference to the accompanying drawings, in which:—

FIG. 1 is a schematic diagram of an example of a system for performingat least one impedance measurement on a subject;

FIG. 2 is a schematic perspective view of an example of a measuringdevice housing;

FIG. 3A is a schematic perspective view of a specific example of a firsthousing;

FIG. 3B is a schematic front view of the first housing of FIG. 3A;

FIG. 3C is a schematic plan view of the first housing of FIG. 3A;

FIG. 3D is a schematic side view of the first housing of FIG. 3A;

FIG. 3E is a schematic underside perspective view of the first housingof FIG. 3A with a base removed;

FIG. 3F is a schematic cut away side view of a load cell mounted thefirst housing of FIG. 3A;

FIG. 3G is a schematic perspective view of a specific example of asecond housing;

FIG. 3H is a schematic front view of the second housing of FIG. 3G;

FIG. 3I is a schematic plan view of the second housing of FIG. 3G;

FIG. 3J is a schematic side view of the second housing of FIG. 3G;

FIG. 3K is a schematic perspective view of a client device support;

FIG. 3L is a schematic perspective view of the client device support ofFIG. 3K mounted to the second housing of FIG. 3G;

FIG. 3M is a rendering of an example of an impedance measuring apparatusincorporating the first and second housings of FIGS. 3A and 3G;

FIG. 4A is a schematic perspective view of a specific example of astand;

FIG. 4B is a schematic front view of the stand of FIG. 4A;

FIG. 4C is a schematic side view of the stand of FIG. 4A;

FIG. 4D is a schematic perspective view of an impedance measuring systemincluding the stand of FIG. 4A and the first and second housings ofFIGS. 3A and 3G;

FIG. 4E is a schematic front view of the system of FIG. 4D;

FIG. 4F is a schematic side view of the system of FIG. 4D;

FIG. 5A is a schematic diagram of an example of a measuring devicesensor configuration;

FIGS. 5B to 5D are schematic diagrams showing example electrodeconfigurations in use for the measuring system of FIG. 5A;

FIG. 6 is a flow chart of an example of an impedance measuring process;

FIG. 7 is a schematic diagram of a distributed system architecture;

FIG. 8 is a schematic diagram of an example of a processing system;

FIG. 9 is a schematic diagram of an example of a client device;

FIGS. 10A to 10C are a flow chart of an example of a measurementprocess;

FIG. 11A is a flow chart of a first example of a process for displayinga body status indicator;

FIG. 11B is a flow chart of a second example of a process for displayinga body status indicator;

FIG. 12 is a schematic diagram of a further example of a system forperforming at least one impedance measurement on a biological subject;

FIG. 13A is a schematic diagram of a second example of an impedancemeasuring system;

FIG. 13B is a schematic diagram of an example of an electrode sheet forthe impedance measuring system of FIG. 13A;

FIG. 13C is a schematic diagram of an example of an alternativeimpedance measuring system; and,

FIG. 13D is a schematic diagram end view of the second housing of theconnectivity module of FIG. 13C.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An example of apparatus suitable for performing at least one impedancemeasurement on a biological subject will now be described with referenceto FIG. 1.

In this example, the measuring system 100 includes an impedancemeasuring device 110, including a measuring device processor 112 coupledto at least one signal generator 113 and at least one sensor 114, whichare in turn coupled to respective drive and sense electrodes 123, 124,via connections, such as wires or leads 122. Two drive and two senseelectrodes are shown in this example, but this is not intended to belimiting and additional electrodes can be provided as will be describedin more detail below.

In use, the signal generator 113 generates a drive signal, which isapplied to the subject S via the drive electrodes 123, whilst the sensor114 measures a response signal via the sense electrodes 124. Thus, inuse, the measuring device processor 112 controls the at least one signalgenerator 113 to cause drive signals to be applied to a subject, with aresponse signal being measured using the at least one sensor 114,allowing the measuring device processor 112 to generate measurement dataindicative of at least one measured impedance value. The measurementdata can include an indication of the measured signals and/or impedancevalues derived therefrom, as will be described in more detail below.

The measuring device 110 is typically in communication with a clientdevice 130, such as a portable computer system, mobile phone, tablet orthe like, allowing the measurement data to be provided to the clientdevice 130, in turn allowing the client device to display an indicatorassociated a result of the impedance measurement.

As part of this, the client device 130 can receive measurement dataincluding an indication of the drive/sense signals and/or measuredimpedance values. The client device 130 can then optionally performfurther processing, for example to determine the impedance indicators,such as indicators of body composition or the like. The client device130 can also combine impedance values or indicators with otherinformation, including indications of disease states or physicalcharacteristics of the subject, determined either by manual user inputor based on signals from one or more physical characteristic sensors.This allows the client device 130 to generate collected subject data,which can then be transferred to a remote processing system, such as aserver or the like for further analysis and/or storage. Additionally,the client device 130 can analyse historical measurement data, eitherstored locally or retrieved from the server, allowing changes inmeasured values over time to be monitored, as will be described in moredetail below.

An example of the physical construction of the measuring device is shownin FIG. 2.

In this example, the measuring device includes first and second housings210, 220. The first housing 210 includes two spaced pairs of foot driveand sense electrodes 123.1, 124.1, which are typically made of spacedapart metal plates provided on an upper surface of the first housing210, thereby forming footplates on which a user can stand. The secondhousing 220 includes two spaced pairs of hand drive and sense electrodes123.2, 124.2 formed from spaced apart metal plates provided on an uppersurface, thereby forming handplates on which a user can rest theirhands.

This arrangement allows the unit to be used by having the user stand onthe first housing, or alternatively sit on a chair, with their feetresting on the foot drive and sense electrodes. The user can then placetheir hands on the hand drive and sense electrodes on second housing,which can be supported by a desk or table in a seated arrangement, or bya stand or other support for a standing arrangement.

The use of two housing containing separate electrodes, therefore allowsimpedance measurements to be performed in a variety of circumstances,and in particular allows measurements to be performed in either seatedor standing arrangements, which is important in ensuring the system canbe used by individuals having restricted physical capabilities.Additionally, the use of metal plate electrodes provided in a housingallows the system to be readily used, and avoids the need forpreparation, such as cleaning of tissue surfaces or removal of hair, toallow wet electrodes to be applied to the skin.

A number of further features will now be described with respect to FIGS.3A to 3M, which show features of the first and second housings in moredetail.

In this example, the first housing 210 is a cuboid having a generallyrectangular side profile, with an isosceles trapezoidal shape in planview, similar to a set of weighing scales. In one example, the housingis formed from moulded upper and lower portions 310.1, 310.2, whichcouple together to define an internal cavity 310.3, which in usecontains required components mounted on a circuit board 315.

The electrodes 123.1, 124.1 are mounted on an upper surface of the upperhousing 310.1, with the electrodes 123.1, 124.1 being made of a thinmetallic plate, such as stainless steel or the like. The electrodestypically have downwardly facing tabs extending through openings in thehousing 310.1, to thereby couple the electrodes to the housing and allowfor electrical connection to the leads within the housing 210. In oneexample, the electrodes 123.1, 124.1 are slightly biased, for example byhaving a smaller spacing between openings in the housing than thedistance between the tabs, so that the electrode curves slightly awayfrom the housing 310.1 in a rest position. As a result, the electrodesbend when weight is applied until the electrodes 123.1, 124.1 restagainst the housing 210, which in turn helps the electrodes 123.1, 124.1conform to a shape of the subject's feet. This provides a greater degreeof comfort and helps ensure good electrical contact.

To further assist with good electrical contact, the electrodes are sizedand positioned to optimise consistent contact with the feet, whilstallowing a range of different feet sizes to be accommodated. In oneexample, the electrodes are spaced apart by at least one of at least 8cm, at least 8.2 cm, at least 8.4 cm, up to 9 cm, up to 8.8 cm, up to8.6 cm, between 8 cm and 9 cm, between 8.2 cm and 8.8 cm, between 8.4 cmand 8.6 cm and more typically approximately 8.5 cm. This enables a rangeof different foot sizes to be accommodated by the electrodes.

The foot drive electrode has a surface area that is at least one of atleast 110 cm, at least 115 cm, at least 120 cm, at least 122 cm, up to140 cm, up to 135 cm, up to 130 cm, up to 218 cm, between 110 cm² and140 cm², between 115 cm² and 135 cm², between 120 cm² and 130 cm²,between 122 cm² and 128 cm², approximately 125 cm² and more typicallyapproximately 124.3 cm². The foot drive electrode has a square orparallelogram shape, with an approximately equal width and length tothereby accommodate different lengths and lateral positions for the ballof the subject's foot, which contacts the drive electrode in use,although other shapes and dimensions could be used.

The foot sense electrode has a surface area that is at least one of atleast 35 cm, at least 40 cm, at least 45 cm, at least 50 cm, up to 70cm, up to 65 cm, up to 60 cm, up to 55 cm, between 35 cm² and 70 cm²,between 40 cm² and 65 cm², between 45 cm² and 60 cm², between 50 cm² and55 cm², approximately 53 cm² and more typically approximately 52.6 cm².The foot sense electrode has a trapezoidal shape with curved edges, witha slightly greater width than length. This is because the position ofthe subject's heel is more constrained that the ball of the foot, by aguiding lip, as will be described in more detail below.

The above described dimensions ensure an approximately consistentsurface area of contact between the subject's feet and the electrodesirrespective of minor variations in feet positioning, which helps ensureconsistent measurements are obtained, allowing variations inmeasurements over time to be tracked more accurately. Additionally, thedimensions allow the apparatus to be used by subjects with a range indifferent feet sizes.

To further assist in controlling foot positioning, the first housing 210includes a raised section 311, defining a lip extending at leastpartially around each pair of foot drive and sense electrodes to therebyguide positioning of a subject's foot relative to the foot drive andsense electrodes in use. In particular, the raised lip includes a rearportion 311.1 configured to engage at least a heel of the user, therebyhelping guide the user in positioning their feet in a longitudinaldirection, whilst the side portions 311.2 of the lip guide feetplacement laterally. Guiding the subject's foot positioning in thismanner can ensure good and more importantly, consistent contact betweenthe feet and electrodes each time the system is used.

In this regard, it will be appreciated that whilst this will still allowfor some minor variation in positioning between different subjects, forexample due to different feet sizes, this helps ensure that any givensubject's feet are provided at a consistent position relative to thedrive and sense electrodes each time the system is used. This providesreproducible positioning, which in turn reduces variations betweensuccessive measurements that could be caused by changes in footposition. Consequently, this helps ensure the system can be used formore reliable longitudinal measurements.

The first housing, and in particular the lower portion 310.2 includesmeasuring device feet 312 that support the first housing spaced from asurface, with supporting ridges 313 extending downwardly andlongitudinally along opposing edges of the lower portion. The supportingridges 313 provide additional stability, and in particular can engagethe floor in the event the apparatus becomes unbalanced, therebypreventing the apparatus from tipping over.

The measuring device feet 312 engage load cells mounted within the firsthousing 210, allowing the measuring device processor 112 to determine aweight of a subject standing on the first housing 210. In order toensure accurate weight measurements are captured, the housing 210contains a rigid internal plate 314, typically made of steel or thelike. The upper housing portion 310.1 engages the plate, so that weightof the user is transmitted to the plate 314.

Each of the measuring device feet 312 include a foot assembly having aload cell mounting 312.1 in the form of a cylindrical body attached toan extending downwardly from an underside of the plate 314, and a footmember 312.2 at least partially positioned within and movable within theload cell mounting 312.1. A load cell 312.3 is coupled to the load cellmounting 312.1 and the foot member 312.2, via respective screws 312.4,so the load cell deforms under relative movement of the load cellmounting 312.1 and foot member 312.2. In use, when a user stands on thehousing 210, the load is transmitted via the rigid plate 314 and theload cell mountings 312.1 to the load cells 312.3, allowing respectiveload signals to be generated, which can in turn be used to calculate thesubject's weight.

The circuitry provided on the circuit board 315, will typically includesignal generators and sensors for the foot drive and sense electrodes.Additionally, the circuitry can include power systems, for example forvoltage conversion or the like. As a result, the board 315 tends to havea slightly elevated temperature, which in turn warms the electrodes,making these more comfortable to stand on.

The second housing 220 is a cuboid having a generally triangular sideprofile, with an isosceles trapezoidal shape in plan view. In oneexample, the housing is formed from moulded upper and lower portions320.1, 320.2, which couple together to define an internal cavity 320.3,which in use contains required components mounted on a circuit board(not shown).

The electrodes 123.2, 124.2 are mounted on an upper surface of the upperhousing 320.1. The electrodes 123.2, 124.2 are typically made of a thinmetallic plate, such as a stainless steel plate, and having tabsextending through openings in the housing 320.1, to thereby couple theelectrodes to the housing and allow for electrical connection to theleads. Again, the electrodes may be raised from the housing 320.1 in arest position, so that the electrodes bend when weight is applied, tohelp the electrodes conform to a shape of the subject's hands. Thisprovides a greater degree of comfort and helps ensure good electricalcontact.

Additionally, an upper surface of the second housing is shaped to atleast partially conform to a shape of a subject's hands. In particular,the second housing has a curved upper surface, to help the subject resttheir hands on the surface even if they are unable to lay their handsout completely flatly, for example due to arthritis, or the like. In oneexample, the hand sense electrode 124.2 contact the subject's palms,with the drive electrodes 123.2 contacting the fingers. In thisinstance, as subject's are more likely to have difficulty straighteningtheir fingers, the radius of curvature of the hand drive electrode isdifferent to, and typically less than a radius of curvature of the handsense electrode, so the hand drive electrode is more curved.

In one example, a radius of curvature of the hand drive electrode is atleast one of at least 100 mm, at least 110 mm, at least 115 mm, at least118 mm, up to 150 mm, up to 130 mm, up to 125 mm, up to 122 mm, between100 mm and 150 mm, between 110 mm and 130 mm, between 115 mm and 125 mm,between 118 mm and 122 mm, approximately 120 mm and more typicallyapproximately 119.5 mm A radius of curvature of the hand sense electrodeis at least one of at least 180 mm, at least 200 mm, at least 210 mm, atleast 215 mm, up to 260 mm, up to 240 mm, up to 230 mm, up to 225 mm,between 180 mm and 260 mm, between 200 mm and 240 mm, between 210 mm and230 mm, between 215 mm and 225 mm, approximately 220 mm and moretypically approximately 218 mm A region between the drive and senseelectrodes typically has an intermediate curvature.

To further assist good electrical contact, over a range of differenthand sizes, the hand drive and sense electrodes in each pair aretypically spaced apart by at least one of at least 3 cm, at least 3.2cm, at least 3.4 cm, up to 4 cm, up to 3.8 cm, up to 3.6 cm, between 3cm and 4 cm, between 3.2 cm and 3.8 cm, between 3.4 cm and 3.6 cm andmore typically approximately 3.5 cm.

To further ensure good electrical contact, and in particular aconsistent contact surface area irrespective of exact positioning, thehand drive electrode typically has a surface area that is at least oneof at least 35 cm, at least 38 cm, at least 40 cm, at least 41 cm, up to50 cm, up to 45 cm, up to 43 cm, up to 42 cm, between 35 cm² and 50 cm²,between 38 cm² and 45 cm², between 40 cm² and 43 cm², between 41 cm² and42 cm², approximately 41 cm² and more typically approximately 41.4 cm².The drive electrode has a curved generally rectangular shape and iswider than long to accommodate lateral movement and splaying of thefingers.

Similarly, the hand sense electrode has a surface area that is at leastone of at least 35 cm, at least 40 cm, at least 45 cm, at least 46 cm,up to 55 cm, up to 50 cm, up to 49 cm, up to 48 cm, between 35 cm² and55 cm², between 40 cm² and 50 cm², between 45 cm² and 49 cm², between 46cm² and 48 cm², approximately 47 cm² and more typically approximately46.8 cm². The hand sense electrode is rectangular, with a cut-outsection that accommodates the guide ridge discussed in more detailbelow. The hand sense electrode is typically twice as wide as it is longto accommodate the position of the thumb as it extends outwardly aroundthe guide ridge.

Additionally, a guide is provided to assist the subject in positioningtheir hands. In one example, this is achieved by having a raised portion321 positioned between each pair of hand drive and sense electrodes, theraised portion defining thumb recesses 321.1 to thereby guidepositioning of a subject's thumbs, with the crook of the thumb engagingthe raised portion, and hence hands relative to each pair of hand driveand sense electrodes in use. In particular, the raised portion includestwo ridges 321.2, each ridge extending towards a respective hand senseelectrodes 124.2, and terminating level with an edge of the senseelectrode closest to the drive electrode, and being adapted to bepositioned between a subject's thumb and forefinger, to thereby guidesubject hand placement.

The second housing can also include a recessed portion 326 along oneedge of an underside surface of the second housing, allowing a user toinsert their fingers between the second housing and a support surface,to thereby more easily lift the second housing. Connector ports in arear face of the first and second housing, for example to receive a lead322 that attaches to the first housing 210, can also positioned beneathan overhang, to thereby reduce ingress of water drops into theconnectors. Finally, the second housing can accommodate a USB port forcharging a tablet or other processing device when coupled thereto.

In this regard, the second housing can include a processing systemmounting 327 that in use receives a support 330, for supporting aprocessing system, such as the client device 130, and in particular atablet, smartphone or other similar client device. In this regard, themounting 327 can include a rectangular plug extending upwardly from anupper surface of the housing, allowing a mounting stem 331 of thesupport 330 to be seated thereon. The support 330 further includes asframe including a back surface 332, and lip 333, on which the clientdevice rests, with retaining lugs 334 extending upwardly from a front ofthe lip to prevent the client device slipping therefrom. This allows atablet or other processing device to be suitably integrated into theconnectivity module.

In one example, the mounting step 331 incorporates a pivotingarrangement, allowing the client device to be rotated about asubstantially vertical axis, so that the client device 130 can facetowards or away from the subject, so that this can be used to allow thesubject or another user, such an operator or clinician, to control themeasurement process and view results. Additionally, the pivotingarrangement can be used to pivot the frame about a horizontal axis,allowing the client device 130 to be tilted, allowing this to be moreeasily viewed by the subject, depending on the subject's height.

In one example, the system can be used in conjunction with a stand andan example of this will now be described with reference to FIGS. 4A to4F.

In this example, the stand 400 includes a base 410 that supports thefirst housing 210, a platform 420 that supports the second housing 220,and a leg 430 coupled to the base 410 and platform 420 to support theplatform 420 relative to the base 410. The stand 400 can be made of anysuitable material, and in one example, includes metal plates, such asaluminium or steel plates, forming the base 410 and platform 420, withthe leg being made of extruded aluminium or the like.

The base and platform typically include mounting lugs 411, 421 whichengage keyhole mountings provided in an underside of the first andsecond housings, allowing the first and second housings to be removablymounted to the base and platform respectively.

The leg typically includes an internal cavity that receives theconnector lead 322, allowing this to pass through the cavity via anopening 431, so this is hidden from view in use.

The leg 430 is typically curved so that a centre of the platform 420 isoffset from a centre of the base 410 in a longitudinal direction, sothat as the subject stands on the first housing the second housing isprovided in front of the subject. The platform is typically spaced fromthe base by a vertical distance of at least one of at least 100 cm, atleast 103 cm, at least 104 cm, at least 105 cm, up to 110 cm, up to 108cm, up to 107 cm, up to 106 cm, between 100 cm and 110 cm, between 103cm and 108 cm, between 104 cm and 107 cm, between 105 cm and 106 cm,approximately 105.5 cm and more typically 105.4 cm. The use of a fixedrelative position between the base and platform means that the subjectis in the same physical position each time a measurement is performed,which helps ensure that changes in readings are as a result of changesin fluid levels and not simply due to redistribution of fluids caused bya change in subject position. It will be appreciated that this allowsconsistent measurements to be performed on a single subject betweendifferent pieces of equipment, allowing measurements to be compared evenif different measuring devices are used.

The stand can incorporate lighting, such as LEDs mounted in theplatform, base or leg, for aesthetic appearances.

In the above example, the apparatus includes four drive electrodes andfour sense electrodes. Accordingly, in one example, a four channelsystem can be provided, and an example of this will now be describedwith reference to FIG. 5A.

In this example, the system includes the measuring device processor 512,which is in turn connected to signal four generators 513, allowing drivesignals to be applied to each of the drive electrodes 123. Eight sensors514 are provided coupled to each of the sense electrodes 124, as well asthe drive electrodes 123, allowing the drive electrodes to be used forsensing, for example when sensing ECG or other body signals.

The measuring device processor 512 is also typically connected to theload cells 312.3, allowing weight measurements to be performed, as wellas a communications module 517 for communication with the client device130.

In use, the measuring device processor selectively controls the foursignal generators 513 and four sensors 514 coupled to the senseelectrodes 124, to perform a sequence of impedance measurements,including segmental impedance measurements and/or whole of bodyimpedance measurements. In this regard, example electrode arrangementsare shown in FIGS. 5B to 5D, with active electrodes being shown filledand inactive electrodes shown as unfilled circles. In these examples,the configuration of FIG. 5B can be used for whole body measurements,whereas the arrangements of FIGS. 5C and 5D are used for the right armand leg respectively. It will be appreciated that other configurationscan be used to measure other limbs, torso, or the like.

The manner in which impedance measurements are performed will now bedescribed in more detail. In particular, the measuring device processor512 is adapted to generate control signals, which cause the signalgenerators 513 to generate one or more alternating signals, such asvoltage or current signals of an appropriate waveform, which can beapplied to a subject S, via the first electrodes 123. The measuringdevice processor 512 also receives an indication of measured responsesignals from the sense electrodes 124 and sensors 514, processing theseand an indication of the applied drive signals to determine impedancevalues. It will be appreciated that the measuring device processor 512may be any form of electronic processing device capable of performingappropriate control, and could include an FPGA (field programmable gatearray), or a combination of a programmed computer system and specialisedhardware, or the like.

The signal generators 513 could be of any appropriate form, but willtypically include digital to analogue converters (DACs) for convertingdigital signals from the processing device to analogue signals, whichare amplified to generate the required drive signals, whilst the sensors514 typically includes one or more amplifiers for amplifying sensedresponse signals and analogue to digital converters (ADCs) to digitisethe analogue response signals and providing digitised response signalsto the processing device.

The nature of the alternating drive signal will vary depending on thenature of the measuring device and the subsequent analysis beingperformed. For example, the system can use Bioimpedance Analysis (BIA)in which a single low frequency signal is injected into the subject S,with the measured impedance being used directly in the determination ofbiological parameters. In one example, the applied signal has arelatively low frequency, such as below 100 kHz, more typically below 50kHz and more preferably below 10 kHz. In this instance, such lowfrequency signals can be used as an estimate of the impedance at zeroapplied frequency, commonly referred to as the impedance parameter valueR₀, which is in turn indicative of extracellular fluid levels.

Alternatively, the applied signal can have a relatively high frequency,such as above 200 kHz, and more typically above 500 kHz, or 1000 kHz. Inthis instance, such high frequency signals can be used as an estimate ofthe impedance at infinite applied frequency, commonly referred to as theimpedance parameter value R_(∞), which is in turn indicative of acombination of the extracellular and intracellular fluid levels, as willbe described in more detail below.

Alternatively and/or additionally, the system can use BioimpedanceSpectroscopy (BIS) in which impedance measurements are performed at eachof a number of frequencies ranging from very low frequencies (1 kHz andmore typically 3 kHz) to higher frequencies (1000 kHz), and can use asmany as 256 or more different frequencies within this range. Suchmeasurements can be performed by applying a signal which is asuperposition of plurality of frequencies simultaneously, or a number ofalternating signals at different frequencies sequentially, depending onthe preferred implementation. The frequency or frequency range of theapplied signals may also depend on the analysis being performed.

When impedance measurements are made at multiple frequencies, these canbe used to derive one or more impedance parameter values, such as valuesof R₀, Z_(c), R_(∞), which correspond to the impedance at zero,characteristic and infinite frequencies. These can in turn be used todetermine information regarding both intracellular and extracellularfluid levels, as will be described in more detail below.

A further alternative is for the system to use Multiple FrequencyBioimpedance Analysis (MFBIA) in which multiple signals, each having arespective frequency are injected into the subject S, with the measuredimpedances being used in the assessment of fluid levels. In one example,four frequencies can be used, with the resulting impedance measurementsat each frequency being used to derive impedance parameter values, forexample by fitting the measured impedance values to a Cole model, aswill be described in more detail below. Alternatively, the impedancemeasurements at each frequency may be used individually or incombination.

Thus, the measuring device 110 may either apply an alternating signal ata single frequency, at a plurality of frequencies simultaneously, or anumber of alternating signals at different frequencies sequentially,depending on the preferred implementation. The frequency or frequencyrange of the applied signals may also depend on the analysis beingperformed.

In one example, the applied signal is generated by a voltage generator,which applies an alternating voltage to the subject S, althoughalternatively current signals may be applied. In one example, thevoltage source is typically symmetrically arranged, with two signalgenerators 313 being independently controllable, to allow the signalvoltage across the subject to be varied, for example to minimise acommon mode signal and hence substantially eliminate any imbalance asdescribed in copending patent application number WO2009059351.

As the drive signals are applied to the subject, the sensors 514 thendetermines the response signal in the form of the voltage across orcurrent through the subject S, using sense electrodes 124. Thus, avoltage difference and/or current is measured between the senseelectrodes 124. In one example, a voltage is measured differentially,meaning that two sensors 514 are used, with each sensor 514 being usedto measure the voltage at each sense electrode 124 and therefore needonly measure half of the voltage as compared to a single ended system.Digitised response signals are then provided to the measuring deviceprocessor 512, which determines an indication of the applied drivesignal and measured response signals, and optionally uses thisinformation to determine measured impedances.

In this regard, the response signal will be a superposition of voltagesgenerated by the human body, such as the ECG (electrocardiogram),voltages generated by the applied signal, and other signals caused byenvironmental electromagnetic interference. Accordingly, filtering orother suitable analysis may be employed to remove unwanted components.

The acquired signal is typically demodulated to obtain the impedance ofthe system at the applied frequencies. One suitable method fordemodulation of superposed frequencies is to use a Fast FourierTransform (FFT) algorithm to transform the time domain data to thefrequency domain. This is typically used when the applied current signalis a superposition of applied frequencies. Another technique notrequiring windowing of the measured signal is a sliding window FFT.

In the event that the applied current signals are formed from a sweep ofdifferent frequencies, then it is more typical to use a signalprocessing technique such as multiplying the measured signal with areference sine wave and cosine wave derived from the signal generator,or with measured sine and cosine waves, and integrating over a wholenumber of cycles. This process, known variously as quadraturedemodulation or synchronous detection, rejects all uncorrelated orasynchronous signals and significantly reduces random noise. Othersuitable digital and analogue demodulation techniques will be known topersons skilled in the field.

In the case of BIS, impedance or admittance measurements are determinedfrom the signals at each frequency by comparing the recorded voltage andthe current through the subject. The demodulation algorithm can thenproduce amplitude and phase signals at each frequency, allowing animpedance value at each frequency to be determined.

Whilst the measured impedance can be used directly, in one example, themeasured impedance is used to derive an impedance parameter, such as animpedance (resistance) at zero frequency, R₀, which equals theextracellular resistance R_(e), or the impedance at a theoreticalinfinite frequency R_(∞), which can be used with R₀ to derive anintracellular resistance R_(i), as well as other impedance parameters.The impedance parameters may be determined in any one of a number ofmanners such as by:

-   -   estimating values based on impedance measurements performed at        selected respective frequencies, solving simultaneous equations        based on the impedance values determined at different        frequencies;    -   using iterative mathematical techniques;    -   extrapolation from a plot of resistance against reactance for        impedance measurements at a plurality of frequencies; and,    -   performing a function fitting technique, such as the use of a        polynomial function.

In one example, the frequencies used are in the range 0 kHz to 1000 kHz,and in one specific example, four measurements are recorded atfrequencies of 25 kHz, 50 kHz, 100 kHz, and 200 kHz, although anysuitable measurement frequencies can be used.

A further alternative for determining impedance parameter values is toperform impedance measurements at a single frequency, and use these asan estimate of the parameter values. In this instance, measurementsperformed at a single low frequency (typically less than 50 kHz) can beused to estimate R₀, measurements at a single high frequency (typicallymore than 100 kHz) can be used to estimate R_(∞), allowing a value ofR_(i) to be determined.

The above described equivalent circuit models the resistivity as aconstant value and does not therefore accurately reflect the impedanceresponse of a subject, and in particular does not accurately model thechange in orientation of the erythrocytes in the subject's blood stream,or other relaxation effects. To more successfully model the electricalconductivity of the human body, an improved CPE based model mayalternatively be used.

When performing measurements of cardiac and/or respiratory parameters,the system is typically used passively, with signals being measured viathe sense electrodes 124 and optionally also via the drive electrodes123. The detected signals are a superposition of voltages generated bythe human body, and will include cardiac and respiratory components,which can typically be isolated through suitable filtering, for example1-40 Hz for cardiac signals and below 1 Hz for respiratory signals.

A typical measurement process using the above described apparatus willnow be described with respect to FIG. 6.

In this example, at step 600 the system acts to detect the presence of asubject. This can be achieved in any suitable manner, and could involvedetecting the weight of a subject standing on the first housing, contactwith the drive or sense electrodes, or activation of a suitableapplication on the client device 130, with this being communicated tothe measuring device.

At step 610, the measuring device processor provides a measurementindication to the client device, thereby allowing the client device 130to display relevant information to the subject at step 620. Theinformation can include any information regarding the measurementprocess, including an indication of the measurement being performed, atime to completion, instructions to the subject, for example asking thesubject to stand still, or the like. This allows the subject to preparefor the measurement, and ensure they are positioned correctly for therelevant measurement being performed. The interface could also displayinformation regarding the measurements, including results, previousmeasurements or the like, as well as questions requesting furtherinformation from the user, such as asking the user questions relating tocurrent symptoms, or the like.

At step 630 the measuring device processor 512 performs a measurementprocedure. Typically multiple measurement procedures are performed insequence, for example by performing a weight measurement, impedancemeasurement and then measurement of cardiac and/or respiratoryparameters. It will be appreciated that the system may be configured toalways perform each of these, or alternatively may be configured to onlyperform selected ones of the procedures depending on the preferredimplementation and/or current settings.

As the measurement process is completed, the measuring device processordetermines measurement data at step 640, which can include raw data,such as values of the magnitude and/or phase of measured signals,processed values, such as impedance values, or the like. The measurementdata is provided to the client device 130, at step 650, allowing clientdevice to display a body status indicator indicative of a body status ofthe subject.

The nature of the body status indicator will vary depending on thepreferred implementation and could include a simple indication ofmeasured parameter values, such as impedance values, a heart rate,respiration rate, or the like. Alternatively, the body status indicatorcould include values derived from the measured parameter values, such asan indication of body composition parameters, an indication of relativewater levels, measurement of a disease state or the like. The bodystatus indicator could be based on current measurements alone, or couldtake into account prior measurements, for example, examining variationsin fluid levels over time.

Accordingly, the above described process can detect the presence of thesubject and then trigger the measurement process, including an impedancemeasurement process, and optionally other measurement processes, withinformation being presented to the subject via the client device.

A number of further features will now be described.

In one example, the body status indicators can include, but are notlimited to any one or more of:

-   -   Body Composition    -   Dry Lean Mass    -   Lean Body Mass    -   Skeletal Muscle Mass    -   Segmental Lean Analysis    -   Body Fat Mass    -   Segmental Fat Analysis    -   BMI (Body Mass Index)    -   Percent Body Fat    -   Visceral Fat Area    -   Visceral Fat Level    -   Total Body Water    -   Intracellular Water    -   Extracellular Water    -   ECW/TBW    -   Segmental Body Water    -   Segmental ECW/TBW    -   Segmental ICW Analysis    -   Segmental ECW Analysis    -   Body-Fat-LBM Control    -   BMR (Basal Metabolic Rate)    -   Leg Lean Mass    -   TBW/LBM    -   Whole Body Phase Angle    -   Segmental Phase Angle    -   Reactance    -   Impedance of Each Segment per frequency    -   Body Water Composition History

In one example, the measuring device processor 512 provides ameasurement indication to the client device, the measurement indicationbeing indicative of a measurement being performed. Thus, the measuringdevice processor 512 can determine a presence of a subject in accordancewith signals from at least one of the load cells and the at least onesensor, commence at least one measurement procedure and provide themeasurement indication to the client device. The client device isresponsive to the measurement indication to display information to thesubject including information regarding the measurement process,measured signals, a body parameter value, a body status indicator,instructions to the subject and a question for the subject. This allowsthe system to automatically commence measurements and display relevantinformation to the subject, so the subject can see the measurement isbeing performed, and allowing them to take appropriate action, such asstanding in a correct position.

In one example, the measuring device processor detects when a subject isstanding on the foot unit in accordance with signals from at least oneof the load cells and causes a weight measurement procedure to beperformed using signals from the load cells. Thus, this can be used toautomatically trigger a weight measurement process when the subjectstands on the first housing. Similarly, the measuring device processordetects when a subject's hands and feet are positioned in contact withthe hand and feet electrodes in accordance with signals from the atleast one sensor and cause a measurement procedure to be performedincluding at least one of an impedance measurement procedure, a cardiacmeasurement procedure and a respiration measurement procedure. Thus, asuitable measurement can be automatically performed depending on thesubject's interaction with the measuring device, with impedance or othermeasurements only being performed when the subject's hands and feet arein contact with the respective electrodes, whilst weight measurementsare performed when the subject's hands are not in contact with the handsense/drive electrodes.

Thus, in one example, the measuring device processor detects when asubject is standing on the foot unit in accordance with signals from atleast one of the load cells, provides weight measurement indication tothe client device, the client device being responsive to the weightmeasurement indication to instruct the subject to stand for a weightmeasurement, before the weight measurement is performed. Following this,the measuring device processor provides a body measurement indication tothe client device, the client device being responsive to the bodymeasurement indication to instruct the subject to place their feet andhands on the respective electrodes, detects when a subject's hands andfeet are positioned in contact with the hand and feet electrodes inaccordance with signals from the at least one sensor and commences animpedance measurement procedure, a cardiac measurement procedure orrespiration measurement procedure. Following this results can bedisplayed to the user. Thus, this allows the subject to be informedthroughout the measurement process, whilst ensuring the process onlyprogresses once the subject is correctly positioned, thereby ensuringaccuracy of the measurements.

A specific example system will now be described in more detail withreference to FIGS. 7 to 9.

In this example, the system 700 includes a number of measuring systems100 coupled via a communications network 740 to one or more processingdevices, such as a server 750, which may in turn be coupled to adatabase 751. This arrangement allows subject data to be collected bythe measurement systems 100 and provided to the server 750 for storageand optional analysis. Collected subject data may be stored in thedatabase 751 together with other information, such as body stateindicators, allowing this information to be remotely accessed and viewedby authorised users, such as clinicians, or the like.

In the above arrangement, the communications network 740 can be of anyappropriate form, such as the Internet and/or a number of local areanetworks (LANs) and provides connectivity between the measuring systems100 and the server 750. It will however be appreciated that thisconfiguration is for the purpose of example only, and in practice themeasuring systems 100 and server 750 can communicate via any appropriatemechanism, such as via wired or wireless connections, including, but notlimited to mobile networks, private networks, such as an 802.11networks, the Internet, LANs, WANs, or the like, as well as via director point-to-point connections, such as Bluetooth, or the like.

Accordingly, it will be appreciated that the client device 130 can be ofany appropriate form and one example is shown in FIG. 8.

In this example, the client device 130 includes at least onemicroprocessor 800, a memory 801, an input/output device 802, such as akeyboard and/or display, and an external interface 803, interconnectedvia a bus 804 as shown. The external interface 803 can be utilised forconnecting the client device 130 to peripheral devices, such as thecommunications networks 740, databases, other storage devices, or thelike. Although a single external interface 803 is shown, this is for thepurpose of example only, and in practice multiple interfaces usingvarious methods (eg. Ethernet, serial, USB, wireless or the like) may beprovided.

In use, the microprocessor 800 executes instructions in the form ofapplications software stored in the memory 801 to allow communicationwith the server 750, for example to allow subject data to be provided tothe sever, or the like.

Accordingly, it will be appreciated that the client device 130 may beformed from any suitable processing system, such as a suitablyprogrammed PC, Internet terminal, lap-top, or hand-held PC, and in onepreferred example is either a tablet, or smart phone, or the like. Thus,in one example, the client device 130 is a standard processing systemsuch as an Intel Architecture based processing system, which executessoftware applications stored on non-volatile (e.g., hard disk) storage,although this is not essential. However, it will also be understood thatthe client devices 130 can be any electronic processing device such as amicroprocessor, microchip processor, logic gate configuration, firmwareoptionally associated with implementing logic such as an FPGA (FieldProgrammable Gate Array), or any other electronic device, system orarrangement.

An example of a suitable server 750 is shown in FIG. 9. In this example,the server includes at least one microprocessor 900, a memory 901, anoptional input/output device 902, such as a keyboard and/or display, andan external interface 903, interconnected via a bus 904 as shown. Inthis example the external interface 903 can be utilised for connectingthe server 750 to peripheral devices, such as the communicationsnetworks 740, databases 751, other storage devices, or the like.Although a single external interface 903 is shown, this is for thepurpose of example only, and in practice multiple interfaces usingvarious methods (eg. Ethernet, serial, USB, wireless or the like) may beprovided.

In use, the microprocessor 900 executes instructions in the form ofapplications software stored in the memory 901 to allow the requiredprocesses to be performed, including communicating with the clientdevices 130, and optionally receiving, analysing and/or displayingresults of impedance measurements. The applications software may includeone or more software modules, and may be executed in a suitableexecution environment, such as an operating system environment, or thelike.

Accordingly, it will be appreciated that the server 750 may be formedfrom any suitable processing system, such as a suitably programmedclient device, PC, web server, network server, or the like. In oneparticular example, the server 750 is a standard processing system suchas an Intel Architecture based processing system, which executessoftware applications stored on non-volatile (e.g., hard disk) storage,although this is not essential. However, it will also be understood thatthe processing system could be any electronic processing device such asa microprocessor, microchip processor, logic gate configuration,firmware optionally associated with implementing logic such as an FPGA(Field Programmable Gate Array), or any other electronic device, systemor arrangement. Accordingly, whilst the term server is used, this is forthe purpose of example only and is not intended to be limiting.

Whilst the server 750 is a shown as a single entity, it will beappreciated that the server 750 can be distributed over a number ofgeographically separate locations, for example by using processingsystems and/or databases 751 that are provided as part of a cloud basedenvironment. Thus, the above described arrangement is not essential andother suitable configurations could be used.

Operation of the system will now be described in further detail withreference to FIGS. 10A to 10C.

For the purpose of these examples it will also be assumed that subjectsuse the client devices 130 to interact with or control the measuringdevice 110, allowing impedance and/or other measurements to be performedand allowing information, such as information regarding physicalcharacteristics, to be collected. This is typically achieved by havingthe subject interact with the system via a GUI (Graphical UserInterface), or the like presented on the client device 130, which may begenerated by a local application, or hosted by the server 750, which istypically part of a cloud based environment, and displayed via asuitable application, such as a browser or the like, executed by theclient device 130. Actions performed by the client device 130 aretypically performed by the processor 800 in accordance with instructionsstored as applications software in the memory 801 and/or input commandsreceived from a user via the I/O device 802. Similarly, actionsperformed by the server 750 are performed by the processor 900 inaccordance with instructions stored as applications software in thememory 901 and/or input commands received from a user via the I/O device902, or commands received from the client device.

The system utilises multiple measuring and client devices 110, 130,which interact with one or more central servers 750, typically formingpart of a cloud based environment. This allows subject data to becollected from a number of different sources, and then aggregated andstored centrally, in turn allowing the system to function as anelectronic medical record system.

Whilst the following example focuses on the analysis of impedanceindicators only, it will be appreciated that the techniques could beextended to include other parameter values, such as other vital signs orthe like, and reference to impedance indicators only is not intended tobe limiting.

However, it will be appreciated that the above described configurationassumed for the purpose of the following examples is not essential, andnumerous other configurations may be used. It will also be appreciatedthat the partitioning of functionality between the measuring device 110,client devices 130, and servers 750 may vary, depending on theparticular implementation.

In this example, at step 1000 the subject optionally activates theclient device 130, which would typically involve opening an applicationinstalled on the client device in order to allow the measurement processto commence.

At this time, the subject may optionally be prompted to provideauthentication information, which may involve supplying biometricinformation, for example by performing an iris scan, fingerprint scan,or the like, or alternatively entering information such as a password,PIN or similar. As a further alternative, authentication information canbe derived from the results of measurements performed below, for exampleby basing authentication information on a combination of measuredparameters, such as a height, weight, and impedance values. Providedauthentication information can then be used to authenticate and identifythe subject, with this being performed locally by the client device 130,or remotely by the server 750 depending on the preferred implementation.

A measurement procedure may also be selected. In this regard a number ofdifferent measurement procedures may be implemented depending on a rangeof factors, such as the software modules loaded onto the client device130, conditions suffered by the subject, body status indicators to bedisplayed, or the like. The process of selecting a measurement procedurecan involve displaying information regarding available measurementprocedures allowing a user to select one of these. Alternatively, thismay be performed automatically, for example by selecting a measurementprocedure based on the software installed on the device. As a furtheralternative this may not be required if identical measurement processesare used irrespective of the information presented to the subject.

At step 1005 the subject stands on the foot unit comprising the firsthousing 210, with the measuring device processor 512 detecting thisbased on signals from the load cells at step 1010. At step 1015, themeasuring device processor 512 generates a weight measurementindication, which is provided to the client device 130 at step 1020,causing the client device to notify the subject that the weightmeasurement is to commence, optionally providing instructions, such asinstructing the subject to stands still with their hands by their sides,to prevent the subject inadvertently resting their hands on the handunit, thereby compromising the weight measurement. Once signals from theweight sensors have reached equilibrium, a weight measurement isperformed and weight data generated.

At step 1030, the measuring device processor 512 provides the clientdevice 130 with a body measurement indication, causing the client deviceto notify the subject to place their hands on the hand unit comprisingthe second housing 220, with their hands and in contact with therespective hand drive and sense electrodes at step 1040. Contact withthe electrodes is detected by applying a drive signal to the driveelectrodes and measuring the response signal to ensure successfulcontact has been achieved at step 1045. It will be appreciated that ifthis has not occurred additional instruction can be provided to thesubject in a manner similar to that outlined above.

At step 1050, impedance measurements are commenced, with a sequence ofdrive signals being applied to respective ones of the drive electrodes,and measurements being performed via respective sense electrodes. Ingeneral, two signal generators are activated at step 1050, so that drivesignals are applied via two of the drive electrodes, with responsesignals being detected via two of the sense electrodes at step 1055.This is repeated for different combinations of electrodes until desiredmeasurements have been performed. In one preferred example, this processis performed to collect impedance measurements at multiple frequencies,and typically 256 or more frequencies, with this being performed tomeasure segmental impedance values for each limb, and the torso, as wellas whole of body impedance measurements.

At step 1060, a cardiac/respiration measurement is performed, with thesensors 514 being activated to measure body signals at step 1065.

At step 1070 the measured signals are used by the measurement deviceprocessor 512 to generate measurement data. The measurement data caninclude raw data or may include partially or fully processed data. Forexample, minimal processing such as filtering of signals is typicallyperformed by the measuring device. Additionally, voltage and currentsignals may be processed in order to determine impedance values such asresistance, reactance and phase angle values. For example, in the caseof BIS, impedance or admittance measurements are determined from thesignals at each frequency by comparing the recorded voltage and thecurrent through the subject. The demodulation algorithm can then produceamplitude and phase signals at each frequency, allowing an impedancevalue at each frequency to be determined. The measurement data caninclude processed signals as well as raw data depending on the preferredimplementation. In general inclusion of the raw data is preferred asthis can allow data to be reprocessed at a later date, for exampleallowing this to be analysed using improved algorithms.

At step 1075 the measurement data is provided to the client device 130,typically using a short range wireless communication protocol such asBluetooth, NFC or the like. The use of a short range protocol reducesthe likelihood of the measurement data being intercepted by thirdparties. Irrespective of this however the measurement data can beencrypted utilising a public key of the client device. With the dataalso further being optionally signed by a private key of the measuringdevice to thereby verify the source of the measurement data and hencehelp ensure measurement data integrity.

At step 1080 the client device 130 may optionally request additionalinformation, with this being provided by the subject at step 1085. Thiscould include requesting authentication information, if this has notpreviously been provided. Alternatively, this could include displaying aquestion to the subject. The question may relate to symptoms or otherinformation required by the system, such as information regardingphysical characteristics, exercise, diet or the like, allowingadditional information regarding the subject to be collected. By doingthis each time a measurement is performed allows a wide range of dataregarding the subject to be collected, without placing an undue burdenon the subject.

It will also be appreciated that other measurements could also beperformed in addition to those outlined above, for example using othersuitable sensing mechanisms. For example, the client device 130 may beequipped with sensors allowing additional information, such as a subjecttemperature to be measured.

The measurement data is collated with any other relevant information,with collected subject data being provided to the server 750 at step1090. The collected subject data typically includes the measurement dataand any additional data, such as responses to questions, data collectedfrom additional sensors, such as physical characteristic data, but mayalso include other data such as environmental data, including but notlimited to location data, temperature data, of the like. The collectedsubject data may be encrypted using a suitable encryption mechanism,such as encrypting the collected subject data using a public key of theserver 750, and optionally signing the collected subject data using aprivate key of the client device 130, thereby ensuring privacy of thecollected subject data is maintained.

At step 1095, the server 250 updates subject data stored in the subjectdatabase 751, by adding the collected subject data. It will beappreciated that this allows subject data relating to the individual tobe collected over time, which in turn enables a comprehensive healthrecord to be established directly from measurement data recorded from ameasuring device. Once subject data has been recorded, this can be usedto generate a body status indicator which is displayed to the subject.The body status indicator can be displayed at any time during theprocess and this does not need to wait until collected subject data hasbeen uploaded to the server. Indeed, this can be performed concurrentlywith the data collection process.

The nature of the body status indicator will vary depending on thepreferred implementation and the nature of the measurement data. Thebody status indication could include a simple recorded value but moretypically examined changes in parameter values such as changes in fluidlevels or the like. The nature of the body status indicator is notimportant for the purposes of the current example and numerous bodystatus indicators will be known to those in the art, for example aslisted above.

In one example the body status indicator is generated locally using theclient device 130, as shown in FIG. 11A.

In this example step 1100 the client device 130 determines if previouslymeasured body parameter values are required. It will be appreciated thatthese may not be required, for example if they are already storedlocally on the client device 130, or if they are not needed to generatethe body status indicator. Assuming previous body parameter values arerequired, at step 1105 the client device 130 generates a subject datarequest which is transferred to the server 250. At step 1110 the server250 retrieves relevant subject data, returning this retrieved subjectdata to the client device 130 at step 1115. At step 1120, the clientdevice 130 calculates the body status indicator, for example bydetermining a change in the body parameter value, causing this to bedisplayed to the subject at step 1125.

At this stage, the client device 130 may also optionally generate anotification, for example based on comparison of the body parametervalue and/or body status indicator to a reference range or othernotification criteria. The notification can be displayed on the clientdevice 130, and may include a motivational message, alert, warning, orthe like. For example, if the user has an unexpectedly high heart rate,or if fluid levels have changed dramatically in a short period of time,a warning may be displayed to the subject directing them to seek medicalattention.

Additionally, and/or alternatively notifications can be provided toother authorised users. For example, subjects can grant specific users,such as medical practitioners, authorization to access their subjectdata. In this instance the client device 130 can generate a notificationand transfer this to an authorised user, such as the subject's doctor,alerting them to a particular event. This can be used to allow themedical practitioner to contact the subject directing them to seekmedical attention.

It will be appreciated that the above-described process may require thatsubject data is retrieved and provided to the client device 130. As analternative to this however the body status indicator could be generatedby the server 250 and transferred to the client device, and an exampleof this will now be described with reference to FIG. 11B.

In this example, the server 250 retrieves required subject data at step1150 and then calculates the body status indicator at step 1155. Thebody status indicator is then transferred to the client device 130 atstep 1160, allowing this to be displayed to the subject at step 1165.The server 250 may then optionally generate a notification at step 1170allowing this to be provided to the client device 130 or a client deviceof an authorised user as required.

A further example of a measuring system will now be described withreference to FIG. 12.

In this example, the system 1200 includes a measuring device 1210coupled to a connectivity module 1220. An optional client device, suchas a computer system, smartphone, tablet or the like, can also beprovided in communication with the measuring device, allowing operationof the measuring device to be at least partially controlled, althoughthis is not essential and will depend on the preferred implementation.

The measuring device 1210 includes a measuring device housing containingat least one signal generator 1213 that generates a drive signal and atleast one sensor 1214 that measures a response signal. A measuringdevice processor 1212 is provided that at least in part controls thesignal generator 1213 and receives an indication of a measured responsesignal from the sensor 1214 allowing the at least one impedancemeasurement to be performed. The measuring device 1210 further includesa first connector 1211 electrically connected to at least the at leastone sensor 1214 and the at least one signal generator 1213.

The connectivity module 1220 includes a connectivity module housing, anda number of electrodes 1223, 1224, that are provided in electricalcontact with the subject S in use. The electrodes can be attached to orform part of the housing, or could be connected to the housing viarespective leads 1222, and example arrangements will be described inmore detail below. The connectivity module also includes a secondconnector 1221 electrically connected to the electrodes 1223, 1224.

In use the measuring device 1210 is connected to the connectivity module1220 by interconnecting the first and second connectors 1211, 1221 sofirst electrodes 1223 are electrically connected to the at least onesignal generator and second electrodes 1224 are electrically connectedto the at least one sensor, thereby allowing a drive signal to beapplied to the subject via the first electrodes 1223 (referred togenerally as drive electrodes) and allowing the response signal to bemeasured via the second electrodes 1224 (referred to generally as senseelectrodes) so that the at least one impedance measurement can beperformed.

In the above described arrangement, a separate measuring device 1210 andconnectivity module 1220 are used, allowing a single type of measuringdevice 1210 to be configured for use with multiple different types ofconnectivity module 1220. This in turn enables a range of differentimpedance measurements to be performed using different configurations ofconnectivity module. In this regard, different electrode arrangements1223, 1224 may be required for performing different types of impedancemeasurement, and so the provision of a common measuring device, anddifferent types of connectivity module allows a single measuring deviceto be used in a wider range of circumstances than would be possible fora single integrated device.

For example, the connectivity module 1220 could include stand-on platesand hand grip electrodes for use in measuring aspects of a subject'sbody composition, whilst adhesive electrodes positioned on the wrist andankles might be preferred for oedema detection, or the like. In thisinstance, by allowing a common measuring device to be selectivelyconnected to different connectivity modules, this allows the mostsuitable electrode configuration to be used, whilst allowing a commonmeasuring device design to be used, which can reduce overall hardwarerequirements and allow for greater efficiencies in manufacture.

Furthermore, in one example, the measuring device 1210 can be adapted tosense the type of connectivity module 1220 to which it is connected,thereby at least partially controlling the impedance measurement processbased on the connectivity module currently being used.

Thus, in this arrangement, a single configuration of measuring device isadapted to be used with connectivity modules that provide onwardconnectivity to the subject. Different types of connectivity modules canbe used with the same measuring device, with the nature of theconnectivity module being used to control the impedance measuringprocesses that can be performed. This allows a user to obtain a singlemeasuring device and then use this with different connectivity modules,allowing different measurements to be performed. This reduces thecomplexity of the measuring device, and allows a single configuration ofmeasuring device to be used in wide range of scenarios. Additionally,this allows users to only acquire connectivity modules that are relevantto measurements that are to be performed, avoiding the need to acquireunnecessary hardware. Finally, this also allows the connectivity modulesto be customised for the particular measurements that are to beperformed, which in turn helps ensure the electrode configuration isoptimised for the particular measurements being performed.

An example of a connectivity module will now be described with referenceto FIGS. 12A and 12B.

In the example of FIG. 13A, the connectivity module includes first andsecond housings 1320.1, 1320.2 which are designed for use with the feetand hands respectively. In this example, the housing 1320.1 is similarin form factor to a set of scales, and includes two spaced pairs of footdrive and sense electrodes 1323.1, 1324.1 forming footplates, on which auser can stand. Conversely, the second housing 1320.2 is in the form ofa tubular body that can be grasped by a user, and which includes twospaced pairs of semi cylindrical hand drive and sense electrodes 1323.2,1324.2 mounted on opposing sides of the body so that these contacts thesubject's hands when the subject grasps the housing 1320.2. The handdrive and sense electrodes 1323.2, 1324.2 are coupled to the firsthousing 1320.1 and hence the connector (not shown) via one or more leads1322. This arrangement allows the user to stand on the first housing1320.1 and grasp the second housing 1320.2, allowing impedancemeasurements to be performed in a manner similar to that describedabove.

In one example, the foot electrodes 1323.1, 1324.1 could be in the formof metal plates mounted within the first housing 1320.1. An alternativearrangement is shown in FIG. 13B. In this example, the foot electrodes1323.1, 1324.1 could be provided on an electrode unit including asubstrate 13211.1 having respective electrodes 1323.1, 1324.1 printedthereon. Tracks 13211.2 extend from the electrodes 1323.1, 1324.1 onto atab 13211.3, which acts to provide a mounting allowing a connector1322.1, typically mounted on the housing 1320.1, to be coupled thereto,thereby electrically connecting the electrodes 1323.1, 1324.1 to thesecond connector (not shown).

A similar arrangement could also be used for the hand electrodes, with asheet having the hand electrodes 1323.2, 1324.2 printed thereon. In thisinstance, the hand electrode sheet could be placed on a desk or table,whilst the connectivity module housing 1320.1 is placed on the floor,allowing the impedance measurements to be performed whilst the subjectis seated.

A further example is shown in FIGS. 13C and 13D.

In this example, the connectivity module 1320 again includes first andsecond housings 1320.1, 1320.2. The first housing 1320.1 has a formfactor similar to a set of scales, and includes two spaced pairs of footdrive and sense electrodes 1323.1, 1324.1 forming footplates, on which auser can stand. The second housing 1320.2 is an elongate housing havingthree portions along its length, with a central rectangular portion1302.21 positioned between two outer semicylindrical portions 1320.22.In this example, the outer semicylindrical portions 1320.22 supportcurved electrode plates 1323.2, 1324.2 mounted on opposing sides of thebody allowing the user to place their palms and fingers on the plates1323.2, 1324.2. In this regard, the curvature of the surface assistswith comfort and ensures good physical and hence electrical contactbetween the user's hands and the electrodes. Meanwhile the centralportion can be used to support the measuring device 1310, and alsooptionally a client device 1330, such as a tablet or the like, which canbe used to control the measurement process as will be described in moredetail below.

It will be appreciated from this that a wide variety of connectivitymodules could be provided, with these being used in differentcircumstances to allow respective types of impedance measurement to beperformed, whilst still using a common measuring device.

Thus, in the above described arrangements, the measuring device isprovided in a measuring device housing that is separate to theconnectivity module housing. This is beneficial in terms of facilitatinguse of a single measuring device with multiple different connectivitymodules, particularly in terms of allowing for measuring device handlingto be performed when attaching or detaching the measuring device andconnectivity modules, without potential to damage components of themeasuring device.

However, it will be appreciated that this is not essential, andalternatively, the measuring device could be provided within theconnectivity module housing, and hence not require a separate measuringdevice housing. This allows the measuring device to be provided in theconnectivity module housing in a manner substantially similar to thatdescribed above, albeit with the measuring device contained entirelywithin the connectivity module housing.

For example, the measuring device could include a circuit board, havingthe relevant components and first connector mounted thereon. This couldbe supported internally within the connectivity module, either throughphysical engagement between the first and second connectors, or throughcooperation with a separate bracket or other mounting. Thus, it will beappreciated that this arrangement could be analogous to the manner inwhich a card, such as a graphics card or RAM is installed in a computersystem housing through attachment to a motherboard, with the measuringdevice corresponding to the card, and the connectivity module thecomputer system and motherboard.

In this latter arrangement, it would be typical, although not essential,for the measuring device to be mounted in a single connectivity module,as opposed to being used interchangeably with different connectivitymodules, to thereby ensure components of the measuring device are notdamaged. Nevertheless, this would still allow for common measuringdevices to be used with a wide range of different connectivity modules,thereby reducing manufacturing complexity and requirements, whilst stillallowing a wide range of functionality to be achieved.

It will be appreciated that features from different examples above maybe used interchangeably where appropriate. Furthermore, whilst the aboveexamples have focussed on a subject such as a human, it will beappreciated that the measuring device and techniques described above canbe used with any animal, including but not limited to, primates,livestock, performance animals, such race horses, or the like. The abovedescribed processes can be used for diagnosing the presence, absence ordegree of a range of conditions and illnesses, including, but notlimited to oedema, lymphodema, body composition, or the like, andreference to specific indicators is not intended to be limiting.

Throughout this specification and claims which follow, unless thecontext requires otherwise, the word “comprise”, and variations such as“comprises” or “comprising”, will be understood to imply the inclusionof a stated integer or group of integers or steps but not the exclusionof any other integer or group of integers.

Persons skilled in the art will appreciate that numerous variations andmodifications will become apparent. All such variations andmodifications which become apparent to persons skilled in the art,should be considered to fall within the spirit and scope that theinvention broadly appearing before described.

We claim: 1) A system for performing at least one impedance measurementon a biological subject, the system including: a) a measuring devicehaving: i) a first housing including spaced pairs of foot drive andsense electrodes provided in electrical contact with feet of the subjectin use; ii) a second housing including spaced pairs of hand drive andsense electrodes provided in electrical contact with hands of thesubject in use; iii) at least one signal generator electricallyconnected to at least one of the drive electrodes to apply a drivesignal to the subject; iv) at least one sensor electrically connected toat least one of the sense electrodes to measure a response signal in thesubject; and, v) a measuring device processor that at least in part: (1)controls the at least one signal generator; (2) receives an indicationof a measured response signal from the at least one sensor; and, (3)generates measurement data indicative of at least one measured impedancevalue; and, b) a client device in communication with the measuringdevice, the client device being adapted to receive measurement dataallowing the client device to display an indicator associated a resultof the impedance measurement. 2) A system according to claim 1, whereinthe drive and sense electrodes are spaced apart metal plates and thefoot drive and sense electrodes are spaced apart by at least one of: a)at least 8 cm; b) at least 8.2 cm; c) at least 8.4 cm; d) up to 9 cm; e)up to 8.8 cm; f) up to 8.6 cm; g) between 8 cm and 9 cm; h) between 8.2cm and 8.8 cm; i) between 8.4 cm and 8.6 cm; and, j) approximately 8.5cm. 3) A system according to claim 1, wherein at least one of: a) thefoot drive electrode has a surface area that is at least one of: i) atleast 110 cm; ii) at least 115 cm; iii) at least 120 cm; iv) at least122 cm; v) up to 140 cm; vi) up to 135 cm; vii) up to 130 cm; viii) upto 218 cm; ix) between 110 cm² and 140 cm²; x) between 115 cm² and 135cm²; xi) between 120 cm² and 130 cm²; xii) between 122 cm² and 128 cm²;xiii) approximately 125 cm²; and, xiv) approximately 124.3 cm²; and, b)the foot sense electrode has a surface area that is at least one of: i)at least 35 cm; ii) at least 40 cm; iii) at least 45 cm; iv) at least 50cm; v) up to 70 cm; vi) up to 65 cm; vii) up to 60 cm; viii) up to 55cm; ix) between 35 cm² and 70 cm²; x) between 40 cm² and 65 cm²; xi)between 45 cm² and 60 cm²; xii) between 50 cm² and 55 cm²; xiii)approximately 53 cm²; and, xiv) approximately 52.6 cm². 4) A systemaccording to claim 1, wherein the first housing includes a raised lip atleast one of: a) extending at least partially around each pair of footdrive and sense electrodes to thereby guide positioning of a subject'sfoot relative to the foot drive and sense electrodes in use; and, b)configured to engage at least a heel of the subject. 5) A systemaccording to claim 1, wherein the first housing includes feet thatsupport the first housing spaced from a surface and wherein the feetengage load cells mounted within the first housing, the measuring deviceprocessor being adapted to determine a weight of a subject standing onthe first housing. 6) A system according to claim 1, wherein the firsthousing includes: a) a rigid internal plate; and, b) four footassemblies, each foot assembly including: i) a load cell mounting on anunderside of the plate; ii) a foot member; and, iii) a load cell coupledto the load cell mounting and the foot member so that the load celldeforms upon application of a load to the rigid plate. 7) A systemaccording to claim 1, wherein the hand drive and sense electrodes ineach pair are metal plates spaced apart by at least one of: a) at least3 cm; b) at least 3.2 cm; c) at least 3.4 cm; d) up to 4 cm; e) up to3.8 cm; f) up to 3.6 cm; g) between 3 cm and 4 cm; h) between 3.2 cm and3.8 cm; i) between 3.4 cm and 3.6 cm; and, j) approximately 3.5 cm. 8) Asystem according to claim 1, wherein at least one of: a) the hand driveelectrode has a surface area that is at least one of: i) at least 35 cm;ii) at least 38 cm; iii) at least 40 cm; iv) at least 41 cm; v) up to 50cm; vi) up to 45 cm; vii) up to 43 cm; viii) up to 42 cm; ix) between 35cm² and 50 cm²; x) between 38 cm² and 45 cm²; xi) between 40 cm² and 43cm²; xii) between 41 cm² and 42 cm²; xiii) approximately 41 cm²; and,xiv) approximately 41.4 cm²; and, b) the hand sense electrode has asurface area that is at least one of: c) at least 35 cm; d) at least 40cm; e) at least 45 cm; f) at least 46 cm; g) up to 55 cm; h) up to 50cm; i) up to 49 cm; j) up to 48 cm; k) between 35 cm² and 55 cm²; l)between 40 cm² and 50 cm²; m) between 45 cm² and 49 cm²; n) between 46cm² and 48 cm²; o) approximately 47 cm²; and, p) approximately 46.8 cm².9) A system according to claim 1, wherein the second housing has acurved upper surface and is shaped to at least partially conform to ashape of a subject's hands. 10) A system according to claim 17, whereina radius of curvature of the hand drive electrode is different to aradius of curvature of the hand sense electrode and wherein at least oneof: a) a radius of curvature of the hand drive electrode is at least oneof: i) at least 100 mm; ii) at least 110 mm; iii) at least 115 mm; iv)at least 118 mm; v) up to 150 mm; vi) up to 130 mm; vii) up to 125 mm;viii) up to 122 mm; ix) between 100 mm and 150 mm; x) between 110 mm and130 mm; xi) between 115 mm and 125 mm; xii) between 118 mm and 122 mm;xiii) approximately 120 mm; and, xiv) approximately 119.5 mm; and, b) aradius of curvature of the hand sense electrode is at least one of: i)at least 180 mm; ii) at least 200 mm; iii) at least 210 mm; iv) at least215 mm; v) up to 260 mm; vi) up to 240 mm; vii) up to 230 mm; viii) upto 225 mm; ix) between 180 mm and 260 mm; x) between 200 mm and 240 mm;xi) between 210 mm and 230 mm; xii) between 215 mm and 225 mm; xiii)approximately 220 mm; and, xiv) approximately 218 mm. 11) A systemaccording to claim 1, wherein the second housing includes a raisedportion between each pair of hand drive and sense electrodes, andwherein at least one of: a) the raised portion defining thumb recessesto thereby guide positioning of a subject's hands relative to each pairof hand drive and sense electrodes in use; and, b) the raised portionincludes two ridges, each ridge extending towards a respective handsense electrodes, and being adapted to be positioned between a subject'sthumb and forefinger. 12) A system according to claim 1, wherein systemincludes a support that supports a client device, the support beingremovably mounted to the second housing and the support includes: a) amounting that removably couples to the second housing; and, b) a framethat receives the client device. 13) A system according to claim 1,wherein the client device is at least one of a tablet and a smartphone.14) A system according to claim 1, wherein the system includes a standincluding: a) a base that supports the first housing; b) a platform thatsupports the second housing; and, c) a leg coupled to the base andplatform to support the platform relative to the base. 15) A systemaccording to claim 14, wherein the leg at least one of: a) is curved sothat a centre of the platform is offset from a centre of the base; and,b) includes a cavity that receives a lead extending between the firstand second housings. 16) A system according to claim 14, wherein theplatform is spaced from the base by a vertical distance of at least oneof: a) at least 100 cm; b) at least 103 cm; c) at least 104 cm; d) atleast 105 cm; e) up to 110 cm; f) up to 108 cm; g) up to 107 cm; h) upto 106 cm; i) between 100 cm and 110 cm; j) between 103 cm and 108 cm;k) between 104 cm and 107 cm; l) between 105 cm and 106 cm; m)approximately 105.5 cm; and, n) 105.4 cm. 17) A system according toclaim 1, wherein the system includes: a) four signal generators, eachsignal generator being electrically connected to a respective driveelectrode; and, b) four sensors, each sensor being electricallyconnected to at least one of the sense electrodes to measure a responsesignal in the subject and wherein the measuring device processorselectively controls the four signal generators and four sensors toperform a sequence of impedance measurements, the impedance measurementsincluding: i) segmental impedance measurements; and, ii) whole of bodyimpedance measurements. 18) A system according to claim 1, wherein themeasuring device includes a communications module for communicating withthe client device and wherein the measuring device processorcommunicates with the client device to at least one of: a) determine theat least one measurement to be performed; b) provide a measurementindication to the client device, the measurement indication beingindicative of a measurement being performed; and, c) provide measurementdata to the client device, the measurement data being indicative of atleast one of: i) measured signals; and, ii) a body parameter valuederived from the measured signals, the body parameter including at leastone of: (1) a respiration parameter; (2) a cardiac parameter; (3) animpedance parameter; and, (4) a weight parameter. 19) A system accordingto claim 1, wherein the measuring device processor: a) commences atleast one measurement procedure; b) provides a measurement indication tothe client device, the client device is responsive to the measurementindication to display an indication of at least one of: i) informationregarding the measurement process; ii) measured signals; iii) a bodyparameter value; iv) a body status indicator; v) instructions to thesubject; and, vi) a question for the subject. c) performs themeasurement; and, d) provides measurement data to the client device, themeasurement data being indicative of at least one of: i) measuredsignals; and, ii) a body parameter value derived from the measuredsignals, the body parameter including at least one of: (1) a respirationparameter; (2) a cardiac parameter; (3) an impedance parameter; and, (4)a weight parameter. 20) A method for performing at least one impedancemeasurement on a biological subject, the system including: a) using ameasuring device having: i) a first housing including spaced pairs offoot drive and sense electrodes provided in electrical contact with feetof the subject in use; ii) a second housing including spaced pairs ofhand drive and sense electrodes provided in electrical contact withhands of the subject in use; iii) at least one signal generatorelectrically connected to at least one of the drive electrodes to applya drive signal to the subject; iv) at least one sensor electricallyconnected to at least one of the sense electrodes to measure a responsesignal in the subject; v) a measuring device processor that at least inpart: (1) controls the at least one signal generator; (2) receives anindication of a measured response signal from the at least one sensor;and, (3) generates measurement data indicative of at least one measuredimpedance value; and, vi) using a client device in communication withthe measuring device, the client device being adapted to receivemeasurement data allowing the client device to display an indicatorassociated a result of the impedance measurement. 21) A system forperforming at least one impedance measurement on a biological subject,wherein the system including a measuring device processor that: a)provides a measurement indication to a client device, the client devicebeing responsive to the measurement indication to display an indicationof at least one of: i) information regarding the measurement process;ii) measured signals; iii) a body parameter value; iv) a body statusindicator; v) instructions to the subject; and, vi) a question for thesubject. b) causes the measurement to be performed; and, c) providesmeasurement data to the client device, the measurement data beingindicative of at least one of: i) measured signals; and, ii) a bodyparameter value derived from the measured signals, the body parameterincluding at least one of: (1) a respiration parameter; (2) a cardiacparameter; (3) an impedance parameter; and, (4) a weight parameter. 22)A method for performing at least one impedance measurement on abiological subject, wherein the method includes, in a measuring deviceprocessor: a) providing a measurement indication to a client device, theclient device being responsive to the measurement indication to displayan indication of at least one of: i) information regarding themeasurement process; ii) measured signals; iii) a body parameter value;iv) a body status indicator; v) instructions to the subject; and, vi) aquestion for the subject. b) causing the measurement to be performed;and, c) providing measurement data to the client device, the measurementdata being indicative of at least one of: i) measured signals; and, ii)a body parameter value derived from the measured signals, the bodyparameter including at least one of: (1) a respiration parameter; (2) acardiac parameter; (3) an impedance parameter; and, (4) a weightparameter.